#distance
#     1 2 3 
#    -4 8 9
x1,y1,z1 = map(int,input().split())#获取向量1的坐标
x2,y2,z2 = map(int,input().split())#获取向量2的坐标
distance = ((x2-x1)**2 + (y2-y1)**2 + (z2-z1)**2)**0.5
print(distance)